Using the negative eigenvalue theory and the infinite order perturbation theory, a new method was developed to solve the eigenvectors of disordered systems. The result shows that eigenvectors change from the extended ...Using the negative eigenvalue theory and the infinite order perturbation theory, a new method was developed to solve the eigenvectors of disordered systems. The result shows that eigenvectors change from the extended state to the localized state with the increase of the site points and the disordered degree of the system. When electric field is exerted, the electrons transfer from one localized state to another one. The conductivity is induced by the electron transfer. The authors derive the formula of electron conductivity and find the electron hops between localized states whose energies are close to each other, whereas localized positions differ from each other greatly. At low temperature the disordered system has the character of the negative differential dependence of resistivity and temperature.展开更多
The Zn(Ⅱ) phthalocyanine sensitized TiO2(ZnPc-TiO2) nanoparticles were prepared by hydrothermal method via impregnation with ZnPc.The as-prepared photocatalysts were characterized by X-ray diffractometry(XRD) and dif...The Zn(Ⅱ) phthalocyanine sensitized TiO2(ZnPc-TiO2) nanoparticles were prepared by hydrothermal method via impregnation with ZnPc.The as-prepared photocatalysts were characterized by X-ray diffractometry(XRD) and diffuse reflectance spectroscopy(DRS),and the surface photovoltage spectroscopy(SPS) and photocatalytic degradation of rhodamine B(RhB) were studied under illuminating.The experimental results indicate that TiO2 sensitized by ZnPc extends its absorption band into the visible region effectively,and the sensitized TiO2 has higher activity than TiO2(Degussa P-25) under the simulated solar light and the visible light.Based on the DRS and SPS results,the mechanism about the photogenerated carrier transfer between TiO2 and ZnPc is proposed.At a lower ZnPc content(≤0.20 μmol/g),ZnPc monomer acts as the electron donor,which provides the photoinduced electrons to the conduction band of TiO2.These photoinduced electrons can transfer to molecular oxygen(O2),leading to the formation of active species,such as superoxide/hydroxide radicals and singlet oxygen,which is beneficial to the photocatalytic reaction.While at a higher ZnPc content(>0.20 μmol/g),the formation of ZnPc dimer results in the decrease of photocatalytic activities of ZnPc-TiO2 photocatalyst.展开更多
Based on Fabry model and finite-different time-domain(FDTD) method, the plasmonic structure composed of a metal-insulator-metal(MIM) bus waveguide and a side-coupled resonator was investigated. It is found that the tr...Based on Fabry model and finite-different time-domain(FDTD) method, the plasmonic structure composed of a metal-insulator-metal(MIM) bus waveguide and a side-coupled resonator was investigated. It is found that the transmission features can be regulated by the cavity width and coupling distance. Electromagnetically induced transparency(EIT)-like transmission can be excited by adding an identical resonator on the pre-existing structure. Combining the foregoing theoretical analysis with coupled mode theory(CMT), the formation process of the EIT-like transmission was detailedly analyzed. EIT-like transmission can also be excited in plasmonic structure with two detuned resonators. By altering the structure parameters, the transparency window can be purposefully modulated. With the merits of compact structure and simplicity in fabrication, the proposed structures may have a broad prospect of applications in highly integrated optical circuits.展开更多
文摘Using the negative eigenvalue theory and the infinite order perturbation theory, a new method was developed to solve the eigenvectors of disordered systems. The result shows that eigenvectors change from the extended state to the localized state with the increase of the site points and the disordered degree of the system. When electric field is exerted, the electrons transfer from one localized state to another one. The conductivity is induced by the electron transfer. The authors derive the formula of electron conductivity and find the electron hops between localized states whose energies are close to each other, whereas localized positions differ from each other greatly. At low temperature the disordered system has the character of the negative differential dependence of resistivity and temperature.
基金Project(20431030) supported by the National Natural Science Foundation of ChinaProject(2006RFQXS096) supported by the Foundation for Science and Technology Innovation Talents of Harbin, China+1 种基金Project(1152Z002) supported by the Key Projects of Educational Department of Heilongjiang Province, ChinaProject(LBH-Q07111) supported by Heilongjiang Postdoctoral Funds for Scientific Research Initiation
文摘The Zn(Ⅱ) phthalocyanine sensitized TiO2(ZnPc-TiO2) nanoparticles were prepared by hydrothermal method via impregnation with ZnPc.The as-prepared photocatalysts were characterized by X-ray diffractometry(XRD) and diffuse reflectance spectroscopy(DRS),and the surface photovoltage spectroscopy(SPS) and photocatalytic degradation of rhodamine B(RhB) were studied under illuminating.The experimental results indicate that TiO2 sensitized by ZnPc extends its absorption band into the visible region effectively,and the sensitized TiO2 has higher activity than TiO2(Degussa P-25) under the simulated solar light and the visible light.Based on the DRS and SPS results,the mechanism about the photogenerated carrier transfer between TiO2 and ZnPc is proposed.At a lower ZnPc content(≤0.20 μmol/g),ZnPc monomer acts as the electron donor,which provides the photoinduced electrons to the conduction band of TiO2.These photoinduced electrons can transfer to molecular oxygen(O2),leading to the formation of active species,such as superoxide/hydroxide radicals and singlet oxygen,which is beneficial to the photocatalytic reaction.While at a higher ZnPc content(>0.20 μmol/g),the formation of ZnPc dimer results in the decrease of photocatalytic activities of ZnPc-TiO2 photocatalyst.
基金Project(61275174)supported by the National Natural Science Foundations of ChinaProject(20100162110068)supported by the Doctoral Program of Higher Education of China
文摘Based on Fabry model and finite-different time-domain(FDTD) method, the plasmonic structure composed of a metal-insulator-metal(MIM) bus waveguide and a side-coupled resonator was investigated. It is found that the transmission features can be regulated by the cavity width and coupling distance. Electromagnetically induced transparency(EIT)-like transmission can be excited by adding an identical resonator on the pre-existing structure. Combining the foregoing theoretical analysis with coupled mode theory(CMT), the formation process of the EIT-like transmission was detailedly analyzed. EIT-like transmission can also be excited in plasmonic structure with two detuned resonators. By altering the structure parameters, the transparency window can be purposefully modulated. With the merits of compact structure and simplicity in fabrication, the proposed structures may have a broad prospect of applications in highly integrated optical circuits.
